Internal diffusion and re-emission of leaked liquid ethyl acetate from mortar materials

Assuming the leakage of hazardous liquid chemicals in factories and chemical plants caused by natural disasters or human error, it is important to precisely estimate exposure risk and design appropriate evacuation plans and risk-reduction measures. The exposure risk of indoor residents to leaked chemicals may be estimated using direct measurements or theoretical/numerical estimations of gas-phase concentrations. Although mathematical models of gas-phase concentration in the workplace are essential for predicting exposure concentrations at the design stage, practical models have not yet been fully established. We previously proposed practical numerical models to assess indoor gas-phase concentration distributions after the accidental leakage of liquid chemicals using liquid toluene as a representative hazardous chemical. In this study, the leakage of liquid ethyl acetate, a commonly used organic solvent, into mortar flooring was reproduced in a small test chamber, and numerical analysis was performed. The results showed that the time history of the chamber exhaust concentration had a sharp peak and differed significantly from that of toluene. Three-dimensional computational fluid dynamics (CFD) analysis incorporating practical ethyl acetate emission models reproduced the external and internal emission characteristics of leaked ethyl acetate on the mortar material. The models showed reasonable agreement with the experimental data.